Ultra-narrow-aisle lift truck

ABSTRACT

An apparatus and method in the form of a vehicle for transporting, lifting, placing and retrieving loads in narrowaisle load storage racks. Narrow-aisle operation is provided by vertically movable, extensible tracks which enter the load space and rest upon the racks thus permitting a track-mounted carriage having lift forks thereon to enter and leave a load space.

United States Patent [1 1 Shaffer Oct. 2, 1973 I 1 ULTRA-NARROW-AISLELIFT TRUCK [75] Inventor: Walter M. Shaffer, Chesterland,

Ohio

[73] Assignee: Townrnotor Corporation, Cleveland,

Ohio

[22} Filed: Dec. 16, 1971 121] App]. No.: 208,576

[52] US. Cl. 214/730, 104/127 [51] Int. Cl B661 9/14 [58} Field ofSearch 214/730, 16.4 A, 214/38 D; 104/48,127, 131

[56] References Cited UNITED STATES PATENTS 3,233,768 2/1966 Turturro eta1. 214/730 3,357,582 12/1967 Wittek 214/512 9/1935 Becker 214/61.1 CB

1,880,374 10/1932 Dahlstrom 214/730 2,915,204 12/1959 Alimanestianm.v 211/6114 A 3,643,825 2/1972 Zane, Jr. 1 214/730 3,606,039 I 9/1971 Westonet a1 1. 214/16.4 A 3,143,081 8/1964 Dolphin et a1. 214/730 PrimaryExaminer-Gerald M. Forlenza Assistant Examiner-Lawrence J. OreskyAtt0rney-Martin Majestic [57] ABSTRACT An apparatus and method in theform of a vehicle for transporting, lifting, placing and retrievingloads in narrow-aisle load storage racks. Narrowais1e operation isprovided by vertically movable, extensible tracks which enter the loadspace and rest upon the racks thus permitting a track-mounted carriagehaving lift forks thereon to enter and leave a load space.

7 Claims, 15 Drawing Figures PMENIEW 2W 3,752,589

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INVENTOR WALTER M. S HAFFEF ATTORNEYS ULTRA-NARROW-AISLE LIFT TRUCKBACKGROUND OF THE INVENTION It has long been a problem in the storageand other industries to maximize the usage of available storage spacewithout resorting to high-cost, limited-use equipment installations.Industry is presently attempting to solve this problem through severalapproaches.

One such approach has been to use lift trucks with a reach-type,pantograph carriage mechanism that is designed to extend into a secondstorage space, thus reducing the number and width of aisles from thatrequired by a standard fork-lift truck. Another approach uses straddletrucks which have extending arms to straddle and support the load andwhich, like the standard truck, must make a 90 turn from the aisle andenter the load storage space to deposit or retrieve a load. Both thereach-type truck and the straddle truck require fouror five-foot wideraisles than the load being carried which is obviously wasteful ofavailable storage space.

Another approach that is more of a single-purpose nature andconsequently much more expensive is using a stacker crane, whichnormally works from an overhead rail. This requires that it be builtinto the warehouse design. The stacker crane requires a working aislewidth two or three feet wider than the loads being handled.

A still further industry approach to the problem is the use of anautomatic warehousing system, wherein a computer provides data storageand is interconnected with an automated storage-retrieval mechanismsimilar to the stacker crane. This later system is costly and is usuallyvery difficult to adapt to an existing warehouse facility.

SUMMARY OF THE INVENTION The present invention overcomes the above-notedproblems by providing an apparatus and method in the form of anextremely narrow-aisle lift truck that makes more efficient use ofwarehousing and storage space by requiring an aisle only slightly widerthan the load itself. This is a major economic advantage since the aislespace saved can be put to productive use as load storage space. Thissubject lift trucks load moment is primarily within its wheel plan, andthis fact coupled with the elevated load and mechanism being closelycontained and partially supported by the warehouse racks, providesa lifttruck which is highly resistant to tipping even when the load is in itshighestextended position.

Another feature provides for the operator riding up with the load, thusproviding him with excellent visibility for a more efficient and safeoperation.

Added to its usefulness in narrow-aisle rack storage of unit loads, thisinvention will also be an effective or der-picker. Furthermore, by notrequiring a 90 turn from the aisle into the stack to store or retrievethe load, as is necessary with present narrow-aisle lift trucks, thisinvention is adaptable to varyingdegrees of automatic control.

Since a significant load moment is not applied to the load-handlingmechanism other than within the traveling carriage, relatively smallstructural members are used, thus greatly reducing the cost ofmanufacturing and further increasing the vehicle's efficiency.

OBJECTS OF THE INVENTION Accordingly, it is a primary object of thisinvention to provide a lift truck that will operate in an aisle no morethan one foot wider than the load being transported, thus making maximumuse of expensive warehouse and storage yard space.

Another object of this invention is to accomplish the above bycontaining the major portion of the load moment within the wheel plan ofthe lift truck, thus making use of relatively small and inexpensivestructural members, and further reducing vehicle cost as well asincreasing vehicle efficiency through the reduction of unproductivevehicle weight.

Also, it is an object of this invention to provide a lift truck whoseload moment is so placed as to allow ex tremely high lifts in a safemanner.

It is a further object of this invention to provide a lift truck havingextensible tracks for supporting the load during deposit and retrievaland also having safety means precluding operation unless the tracks arefully supported.

It is a further object to provide a vehicle whereby the operator ridesup with the load, thus assuring excellent visibility and a highlyefficient and safe operation.

A further object of this invention is to provide a more versatile lifttruck that will be adaptable to varying degrees of an automated-controlwarehousing system.

Additional advantages and features of the present invention are madeapparent in the following description and the accompanying drawings,wherein:

\ FIG. 1 is a perspective view of the invention, from the operatorplatform side, showing the carriage assembly and operator platform inits highest, raised position;

FIG. 2 is a top plan view of the invention;

FIG. 3 is a side elevation view partially cut away to show the operatingmechanism for providing small incremental movement of the forks relatveto the major carriage member;

FIG. 4 is a front elevation of the invention showing the tracks fullyextended;

FIG.'5 is a cross-sectional view taken as shown in FIG. 2;

FIG. 6 is a cross-sectional view of the carriage guide rail as shown inFIG. 4;

FIG. 7 is a similarview of the carriage guide rail, as shown in FIG. 4;and

FIGS. 8-15 are schematic drawings setting forth a sequence of loadhandling operations.

DETAILED DESCRIPTION Referring now in detail to FIGS. 1-3 of thedrawings, the inventive lift truck generally at 10 comprises a bodyportion 12 containing power and control components (not shown). Thepower source may consist of batterypowered electric motor means, aninternal combustion engine coupled through a mechanical or hydrostaticdrive means to the single steerable drive wheel 14, or such other.motive power means or combination of means known to those well skilledin the art.

A transverse, forward frame member 16 is joined to the body portion 12by means of a longitudinal side frame member 18. Forward and aft mastassemblies 20 and 22 with their associated carriages 24 and 26,respectively, are provided for vertical positioning of the load carriagemeans. Mast assembly 22 is mounted on body portion 12, while mastassembly 20 is mounted on the forward frame member 16. The two forwardnonsteerable wheels 28 are also secured at each end of the forward framemember 16, by conventional axle suspension means (not shown).

Four guide rollers 30 at the four corners of the vehicle are spaced atthe correct width and height to properly mate with the warehouselongitudinal rack members 32, thus providing additional guidance for thelift truck when it is traversing the storage aisles. Steering of thepowered wheel 14 is accomplished by means of a manually operablesteering wheel 34 with its columnmounting integral with the rigid bodyportion 12.

The operator station 36 contains all other controls (not shown) andmoves with the stationary transverse track sections 38 and the movablecarriage assembly 40, thus permitting the operator compartment 12 tomove vertically with the load handling portion of the truck, showngenerally at 42. It is understood that alternatively the steering wheelcould also move vertically with the operator station or compartment.

The carriage assembly 40 has mounted thereon a pair of forks 44 and 46for supporting the load 48 to be transported, and forms a traversingunit 50 in combination with the side members 52 and 54. Each side membercontains a pair of rollers 56 mounted in recesses on its underside, forengaging the track section members 38.

As shown in FIG. 3, a pair of hydraulic jacks 58 and 60 in combinationwith bellcrank linkages 62, 64, permit a limited amount of verticalmovement for raising and lowering the load independently of the carriagelift mechanism, with such movement being necessary to raise or lower theload to the warehouse racks or floor without moving the guide tracks.Stationary transverse track sections 38 serve to support both the loadcarriage and the two sections of folding transverse track members 66 and68, all having the same top contour. The folding track sections 66 arepivotally joined to carriage members 38 by a rotary hinge means 70, andthe folding track section 66 is pivotally joined to the track member 68by rotary hinge means 72.

Turning now to FIG. 5, the track extension sequence, from travelingposition to load/unload position, will be described. Operator activationof the hydraulic jack means 74, causes the folding track member 66 torotate clockwise and assume position 66'. At the same time, foldingtrack member 66 rotates clockwise, folding track member 68 rotatescounterclockwise to assume its position 68.

Thus, the lower surfaces of the transverse folding track members 66 and68 will have engaged the warehouse storage space floor as shown in FIG.4, or, if the carriage lift member 40 is in the upper position, as shownin FIGS. 12-15, said track members will rest upon the warehouse rackassembly 76 supported by members 78 and 80.

Returning to FIG. 5, the mechanism for extending the track sectionsincludes a link member 82 which is pivotally attached at one end atpivot means 84 on the track members 38 and is guided by the internalwalls of of hollow track sections 66. A support roller means 86 isattached to the other end of link 82. As best seen in FIG. 4, rollermeans 86 rolls against the surface 88 on the underside of folding trackassembly 68 allowing it to move smoothly from its vertical travelingposition 68 to its horizontal load/unload position. The sequence ofoperation is reversed for folding the track back into its travelingposition.

When the truck is in the load/unload condition and the track ishorizontally extended into the warehouse storage space, a smooth,continuous load-support track is presented for the subsequent transversemovement of the traversing unit 50.

Turning to FIGS. 5-7, it may be seen that rollers 56 conform to thecontoured upper surface of track members 38, 66 and 68. The rollers 56are mounted on the bottom of the carriage side members 52 and 54, andhave a fixed scraper member 90 in front and behind the rollers 56 toclear debris from the track top surface, thus always presenting a clean,smooth track surface to the rollers.

As best seen in FIG. 2, the transverse movement of the carriage assemblyor traversing unit 50 and load 48 is provided by chains 92 and 94attached to side members 52, 54, chain sprockets 96, and chain guides 98attached to transverse track sections 38 by conventional means (notshown). A very small rotary hydraulic motor means, or other such motormeans readily known to one skilled in the art, is used to drive thechain sprocket mechanism thereby propelling the carriage and load ontothe track sections 66 and 68. The carriage forks vertical movement isthen actuated through hydraulic jacks 58 and 60 and bellcranks 62 and 64as best seen in FIG. 3 to deposit the load on the warehouse rack orfloor.

As seen in FIG. 4, a safety feature is also included whereby the chaindrive sprocket motor means cannot be energized if the folding trackmembers 66 and 68 are not in a safe, supported position on the warehousefloor or rack. This is accomplished by means of a plunger 100, locatedin the lower surface of the outer track member 68, which is depressed byeither the warehouse floor or warehouse rack assembly 76 and therebyactuates a safety switch mechanism (not shown) connected to the chainsprocket motor means.

The method of operation of my invention will now be described withparticular reference to FIGS. 8-15 of the drawings. The first step isshown in FIG. 8 wherein lift truck 10 is driven in a storage aisle to apoint adjacent to a load 48, which load is contained in a load storagespace defined by top rack assembly 76 and members 78 and 80. As shown inFIG. 9, the next step is the extension of folding track sections 66, 68into the load space, with one of each pair of track sections resting onthe ground on either side of load 48.

The next step, shown in FIG. 10, is to propel the traversing unit orcarriage into the load space on the track sections by chain means (notshown). It may be parenthetically noted that the load moment on thevehicle is minimized due to the ability of the track sections totransmit much of the weight of the load to the supporting ground attheir point of contact therewith. Actuation of fork means (not shown) isthen accomplished to lift the load from its supporting surface whereuponthe chain means is reversed to retract the traversing unit and load intothe vehicle to the position shown in FIG. 1 l.

The track members are then retracted for subsequent movement of thevehicle.

If a higher load space is to be serviced, the load handling portion 42of the truck including the operator station is raised by activating thelift mast means 102 as shown in FIG. 12. The above steps are thenrepeated as shown in FIGS. 13-15, however, reversing the steps todeposit the load.

One embodiment of my invention has been fully described, but it will beapparent to anyone skilled in the art that various other forms would bepossible without departing from the spirit of the invention or the scopeof the following claims.

What is claimed is:

l. A lift truck for use in narrow storage aisles comprising,

a body,

a pair of track members pivotally attached, to the body by pivot means,said track members being extendible so as to enter an adjacent loadspace,

means forextending said track members,

carriage means including lift fork means thereon adapted for raising andlowering loads,

means for propelling said carriage means on said track members into anadjacent load space for retrieving or depositing loads,

safety means rendered operative by extending said track members intosupporting contact with a support surface for preventing propelling ofthe carriage means when the track means is not fully supported.

2. The lift truck of claim 1 further including mast means for raisingand lowering said track means whereby higher load spaces can beaccommodated.

3. The lift truck of claim 1 wherein the means for propelling thecarriage means comprises chains and sprockets mounted on the trackmeans.

4. The lift truck of claim 1 wherein the lift fork means compriseshydraulic cylinder means operatively connected to a pair of lift forksby linkage means.

5. The lift truck of claim 1 wherein the means for extending said trackmembers comprise hydraulic jacks operatively connected to said trackmembers for movement thereof.

6. The lift truck of claim 1 further including an operator platformoperatively connected to said track means for vertical movementtherewith whereby enhanced operator visibility is provided.

7. The lift truck of claim 1 further including a plurality of guidewheels mounted on said body for facilitating negotiation of narrowaisles by the lift truck.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No-3,762,589 Dated October 2, 1973 Inventor M It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

In the heading:

"Townmotor" should read --Towrriotor--.

Columh 1, line 16 "dard truck" should read -dard fork lift truck--.

4 Signed and sealed this 30th day of April 19%..

(SEAL) Attest:

EDwAl-ZD I-LrLETCIiElQJH. C. I lARSHALIJ DAL-IN A'btestiz'lg OfficerCommissioner of Patents FQRM Po-1o5o (10 59)

1. A lift truck for use in narrow storage aisles comprising, a body, apair of track members pivotally attached to the body by pivot means,said track members being extendible so as to enter an adjacent loadspace, means for extending said track members, carriage means includinglift fork means thereon adapted for raising and lowering loads, meansfor propelling said carriage means on said track members into anadjacent load space for retrieving or depositing loads, safety meansrendered operative by extending said track members into supportingcontact with a support surface for preventing propelling of the carriagemeans when the track means is not fully supported.
 2. The lift truck ofclaim 1 further including mast means for raising and lowering said trackmeans whereby higher load spaces can be accommodated.
 3. The lift truckof claim 1 wherein the means for propelling the carriage means compriseschains and sprockets mounted on the track means.
 4. The lift truck ofclaim 1 wherein the lift fork means comprises hydraulic cylinder meansoperatively connected to a pair of lift forks by linkage means.
 5. Thelift truck of claim 1 wherein the means for extending said track memberscomprise hydraulic jacks operatively connected to said track members formovement thereof.
 6. The lift truck of claim 1 further including anoperator platform Operatively connected to said track means for verticalmovement therewith whereby enhanced operator visibility is provided. 7.The lift truck of claim 1 further including a plurality of guide wheelsmounted on said body for facilitating negotiation of narrow aisles bythe lift truck.